LG OM7560 Service Manual page 39

NO SOUND
There is no sound output in the MIC IN function, repair the set according to the following guide.
6-7. MIC IN function
6-7-1. Solution
Replace IC206 on MAIN board, ICA301 on TOP FRONT board.
6-7-2. How to troubleshoot (Countermeasure)
1) Check MIC_SI & MIC_S2 signal to pin5 & 6 of CN201.
  If no signal, Check the signals to pin6 & 8 of CNA301 on the FRONT board.
Check if the signal is entered from pin 6 & 8 of CNA301 to pin 5 & 6 of CN201.
2) Check if MIC_SIG is entered from pin 6 of JK302 & JKA303 to pin2, 13 to ICA301 (PRE AMP).
3) Check if the amplified signal comes out from pin3 &12 of ICA301.
  If no signal output, check DVCC_3.3V for ICA301, replace ICA301 with a new one if it has a problem.
4) Check if MCS_BCK, MCS_MLCK & MCS_LRCK is entered from IC501 to IC206.
Check if MIC_DATA_IN is entered from pin9 of IC206 to pin T1of IC501.
  If no signal, check DVCC_5V & DVCC_3.3V for IC206.
If it is abnormal, change replace it a new one.
5) Check the following I2S signal flow from IC206 to IC501.
  If there is any trouble, check the power for each IC.
If the signals are abnormal, replace it a new one.
6) Check if the digital audio AMP block is okay. Refer to "Digital Audio AMP" guide on item 6-1.
  If AMP is damaged, replace it with a new one.
6-7-3. Service hint (Any picture/ Remark)
ONE POINT REPAIR GUIDE
ADC/ MIC_DATA: pin9 ADC/ MIC_DATA: pin9
MCS_BCK: pin8 MCS_BCK: pin8
MCS_LRCK: pin7 MCS_LRCK: pin7
MCS_MCLK: pin6 MCS_MCLK: pin6
< MAIN board bottom view >
IC206 IC206
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